US8867735B2 - Echo cancelling device, communication device, and echo cancelling method having the error signal generating circuit - Google Patents
Echo cancelling device, communication device, and echo cancelling method having the error signal generating circuit Download PDFInfo
- Publication number
- US8867735B2 US8867735B2 US13/619,836 US201213619836A US8867735B2 US 8867735 B2 US8867735 B2 US 8867735B2 US 201213619836 A US201213619836 A US 201213619836A US 8867735 B2 US8867735 B2 US 8867735B2
- Authority
- US
- United States
- Prior art keywords
- signal
- echo
- spurious
- adaptive filter
- error
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related, expires
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M9/00—Arrangements for interconnection not involving centralised switching
- H04M9/08—Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic
- H04M9/082—Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic using echo cancellers
Definitions
- the present invention relates to an echo cancelling technology used in a communication device.
- the present invention relates to the echo cancelling technology in a double talk state.
- FIG. 3 illustrates a structure of the echo canceller described in “Technology of Digital Audio” written and edited by Nobuhiko Kitawaki, issued by the Telecommunications Association, distributed by Ohmsha, Ltd. ISBN4-88549-905-4.
- a signal transmitted from a mobile terminal on the near end talker side to a mobile terminal on the far end talker side is a transmitting signal e(k).
- a signal received by the mobile terminal on the near end talker side from the mobile terminal on the far end talker side is a receiving signal x(k).
- the receiving signal x(k) is delivered from a speaker of the mobile terminal on the near end talker side.
- the near end talker is performing a hands free talk.
- an echo signal y(k) is generated by sneaking of the receiving signal x(k) delivered from the speaker, and is received by a microphone of the mobile terminal on the near end talker side.
- This echo signal y(k) is expressed by Equation (1).
- y ( k ) h ( k ) ⁇ x ( k ) Equation (1)
- the parameter h(k) in Equation (1) is a conversion coefficient from the receiving signal x(k) into the echo signal y(k).
- the conversion coefficient h(k) indicates a transmission characteristic of an acoustic echo path from the speaker to the microphone, which depends on an environment in which the mobile terminal on the near end talker side is placed.
- a voice signal v(k) of the near end talker and an ambient noise signal n(k) are also received by the microphone of the mobile terminal on the near end talker side.
- an input signal yin(k) received by the microphone of the mobile terminal on the near end talker side is expressed by Equation (2).
- the echo canceller illustrated in FIG. 3 includes an adaptive filter and a subtractor so as to cancel the echo signal y(k).
- the adaptive filter synthesizes a spurious echo signal y′(k) from the receiving signal x(k) based on the NLMS algorithm.
- This spurious echo signal y′(k) is an echo signal estimated by the adaptive filter and is expressed by Equation (3).
- y ′( k ) h ′( k ) ⁇ x ( k ) Equation (3)
- the parameter k′(k) in Equation (3) is a conversion coefficient from the receiving signal x(k) into the spurious echo signal y′(k).
- the conversion coefficient h′(k) indicates a transmission characteristic of the acoustic echo path from the speaker to the microphone, which is estimated by the adaptive filter.
- the adaptive filter delivers the obtained spurious echo signal y′(k) to the subtractor.
- the subtractor receives the input signal yin(k) from the microphone. Then, the subtractor generates the transmitting signal e(k) by subtracting the above-mentioned spurious echo signal y′(k) from the received input signal yin(k).
- the transmitting signal e(k) generated by the subtractor is expressed by Equation (4).
- the adaptive filter illustrated in FIG. 3 performs feedback control based on the transmitting signal e(k). Specifically, the adaptive filter updates the above-mentioned conversion coefficient h′(k) so that the transmitting signal e(k) becomes zero.
- the transmitting signal e(k) generated by the subtractor is expressed by Equation (5).
- e ( k ) y ( k ) ⁇ y ′( k ) Equation (5)
- the adaptive filter updates the above-mentioned conversion coefficient h′(k) so that the transmitting signal e(k) expressed by Equation (5) becomes zero.
- the adaptive filter estimates the transmission characteristic h(k) of the acoustic echo path from the speaker to the microphone so that the echo signal y(k) received by the microphone is cancelled.
- the transmitting signal e(k) expressed by Equation (5) is an estimated error, and it can be said that the adaptive filter performs the feedback control so that the estimated error e(k) becomes zero.
- the spurious echo signal y′(k) agrees with the actual echo signal y(k), whereby echo cancellation is normally performed.
- the adaptive filter performs the feedback control so that the transmitting signal e(k) expressed by Equation (4) becomes zero, and hence it is impossible to remove only the echo signal y(k) normally.
- the adaptive filter misestimates the transmission characteristic h(k) due to a disturbance other than the echo signal y(k) received by the microphone, with the result that the performance of the echo cancellation is deteriorated significantly.
- the echo canceller illustrated in FIG. 3 becomes unstable with respect to a disturbance, and particularly in the double talk state, the performance of the echo cancellation is deteriorated significantly.
- a related technology for a purpose of solving the above-mentioned problem is described in Japanese Patent Application Laid-open No. 2002-76999.
- FIG. 4 illustrates a structure of the echo canceller described in Japanese Patent Application Laid-open No. 2002-76999.
- the echo canceller illustrated in FIG. 4 includes a power estimation circuit 103 , a step size decision circuit 104 , a noise level estimation circuit 106 , and a near end voice level estimation circuit 107 in addition to an adaptive filter 101 and a subtractor 102 .
- the adaptive filter 101 synthesizes the spurious echo signal y′(k) from the receiving signal x(k), and the subtractor 102 subtracts the spurious echo signal y′(k) from the input signal yin(k) so as to generate the transmitting signal e(k).
- the transmitting signal e(k) is the same as that expressed by Equation (4).
- the power estimation circuit 103 estimates power of the receiving signal x(k) based on the receiving signal x(k) from the far end talker.
- the noise level estimation circuit 106 and the near end voice level estimation circuit 107 respectively estimate levels of the ambient noise signal n(k) and the voice signal v(k) based on the transmitting signal e(k).
- the step size decision circuit 104 decides a step size based on the estimated power of the receiving signal x(k), the estimated level of the ambient noise signal n(k) and the estimated level of the voice signal v(k).
- the step size means an update quantity of the conversion coefficient h′(k) in the adaptive filter 101 . For instance, when the estimated level of the voice signal v(k) or the ambient noise signal n(k) is relatively small, i.e., when it is determined that the input signal yin(k) received by the microphone is mainly the echo signal y(k), the step size decision circuit 104 sets the step size to be relatively large.
- the step size decision circuit 104 sets the step size to be relatively small.
- the step size (update quantity) decided in this way is supplied to the adaptive filter 101 together with the transmitting signal e(k).
- the adaptive filter 101 updates the conversion coefficient h′(k) so that the transmitting signal e(k) becomes zero.
- the adaptive filter 101 updates the conversion coefficient h′(k) in accordance with the step size decided by the step size decision circuit 104 .
- the adaptive filter 101 updates the conversion coefficient h′(k) by the large step.
- the adaptive filter 101 updates the conversion coefficient h′(k) by the small step.
- the echo canceller illustrated in FIG. 4 estimates the level of the voice signal v(k) and the ambient noise signal n(k) which are contained in the input signal yin(k), and sets the update quantity of the conversion coefficient h′(k) to be variable in accordance with the situation.
- the transmission characteristic h(k) from being largely misestimated by the adaptive filter 101 , whereby the stability with respect to the disturbance is improved.
- Japanese Patent Application Laid-open No. 2008-141734 discloses an echo canceller that is used for a loudspeaker call system for performing a loudspeaker call using a speaker and a microphone.
- the echo canceller includes an adaptive filter portion and an echo suppressing portion.
- the adaptive filter portion identifies an impulse response of a feedback path constituted of an acoustic connection between the speaker and the microphone, in an adaptive manner, and estimates an echo component of the feedback path based on an input signal supplied to the feedback path. Further, the adaptive filter portion subtracts the estimated echo component from a microphone input signal supplied from the feedback path.
- the echo suppressing portion performs an echo suppressing process on an echo cancellation output signal delivered from the adaptive filter portion.
- the echo suppressing portion determines an echo suppressing quantity based on a Wiener filtering method by using an echo reducing quantity that is defined based on a ratio between the above-mentioned microphone input signal and a voice signal on the near end side which mixes in the feedback path. Then, the echo suppressing portion multiplies the echo suppressing quantity and the echo cancellation output signal delivered from the adaptive filter portion together.
- the step size is decided based on three parameters including the estimated power of the receiving signal x(k), the estimated level of the ambient noise signal n(k), and the estimated level of the voice signal v(k).
- an echo cancelling device comprises: an adaptive filter; a subtractor; and an error signal generating circuit.
- the adaptive filter synthesizes a spurious echo signal from a receiving signal before being delivered from a speaker.
- the subtractor subtracts the spurious echo signal from an input signal received by a microphone so as to generate an echo cancellation signal.
- the error signal generating circuit generates an error signal by removing a spurious voice signal corresponding to a voice signal of a talker from the echo cancellation signal.
- the adaptive filter updates a characteristic of the adaptive filter so that an amplitude of the error signal becomes smaller.
- a communication device comprises: a microphone which receives an input signal; a speaker which delivers a receiving signal; and an echo cancelling device.
- the echo cancelling device includes: an adaptive filter which synthesizes a spurious echo signal from the receiving signal before being delivered from the speaker; a subtractor which subtracts the spurious echo signal from the input signal so as to generate an echo cancellation signal; and an error signal generating circuit which generates an error signal by removing a spurious voice signal corresponding to a voice signal of a talker from the echo cancellation signal.
- the adaptive filter updates a characteristic of the adaptive filter so that an amplitude of the error signal becomes smaller.
- an echo cancelling method comprises: (A) synthesizing, by means of an adaptive filter, a spurious echo signal from a receiving signal before being delivered from a speaker; (B) subtracting the spurious echo signal from an input signal received by a microphone so as to generate an echo cancellation signal; (C) generating an error signal by removing a spurious voice signal corresponding to a voice signal of a talker from the echo cancellation signal; and (D) updating a characteristic of the adaptive filter so that an amplitude of the error signal becomes smaller.
- the echo cancelling technology of the present invention stability of the adaptive filter is enhanced with respect to disturbances except for the echo signal received by the microphone. As a result, an excellent echo cancellation performance can be obtained in a double talk state as well.
- FIG. 1 is a conceptual diagram illustrating a principle of generation of an echo
- FIG. 2 is a conceptual diagram illustrating a howling sound
- FIG. 3 is a block diagram illustrating a structure of an echo canceller according to a related technology
- FIG. 4 is a block diagram illustrating a structure of an echo canceller according to another related technology
- FIG. 5 is a schematic diagram illustrating a structure of a mobile terminal according to an embodiment of the present invention.
- FIG. 6 is a block diagram illustrating a structure of an echo canceller (echo cancelling device) according to the embodiment of the present invention.
- FIG. 7 is a flowchart illustrating an operation of the echo canceller according to the embodiment of the present invention.
- the echo cancelling technology according to this embodiment can be applied to a communication device such as a mobile phone, a mobile terminal, a fixed telephone, a communication conference terminal, or the like.
- FIG. 5 schematically illustrates a mobile terminal 1 as an example of the communication device to which the echo cancelling technology of this embodiment is applied.
- the mobile terminal 1 includes a microphone 2 (input portion), a speaker 3 (output portion), an antenna 4 , and a display 5 .
- the mobile terminal 1 receives speech data from another mobile terminal via the antenna 4 and transmits speech data to the another mobile terminal.
- the mobile terminal 1 illustrated in FIG. 5 has a videophone function, for example, and a user (near end talker) can perform hands free talk by using the mobile terminal 1 .
- the display 5 displays an image of a far end talker and the like, and the speaker 3 delivers a voice of the far end talker.
- a voice of the near end talker, ambient noise, an echo, and the like are received by the microphone 2 .
- the mobile terminal 1 of this embodiment is further equipped with an echo canceller (echo cancelling device) 10 .
- FIG. 6 is a block diagram illustrating a structure of the echo canceller 10 according to this embodiment.
- the echo canceller 10 of this embodiment includes an adaptive filter 20 , a first subtractor 30 , and an error signal generating circuit 40 .
- the error signal generating circuit 40 includes a residual echo suppressor 41 , a noise suppressor 42 , and a second subtractor 43 .
- a signal transmitted from the mobile terminal 1 via the antenna 4 to the mobile terminal on the far end talker side is a transmitting signal e(k).
- a signal received by the mobile terminal 1 via the antenna 4 from the mobile terminal on the far end talker side is a receiving signal x(k).
- the receiving signal x(k) is delivered from the speaker 3 of the mobile terminal 1 .
- it is supposed that the near end talker is performing the hands free talk. Therefore, an echo signal y(k) generated by sneaking of the receiving signal x(k) delivered from the speaker 3 is received by the microphone 2 of the mobile terminal 1 .
- This echo signal y(k) is expressed by Equation (6).
- y ( k ) h ( k ) ⁇ x ( k ) Equation (6)
- the parameter h(k) in Equation (6) is a conversion coefficient from the receiving signal x(k) to the echo signal y(k).
- the conversion coefficient h(k) indicates a transmission characteristic of an acoustic echo path from the speaker 3 to the microphone 2 , which depends on an environment in which the mobile terminal 1 is placed.
- a voice signal v(k) of the near end talker and an ambient noise signal n(k) are also received by the microphone 2 of the mobile terminal 1 .
- an input signal yin(k) received by the microphone 2 of the mobile terminal 1 is expressed by Equation (7).
- yin ( k ) v ( k )+ n ( k )+ y ( k ) Equation (7)
- k denotes time as to the parameters described above. The same is true in the following description.
- FIG. 7 is a flowchart illustrating an operation of the echo canceller 10 according to this embodiment.
- the operation of the echo canceller 10 according to this embodiment is described in detail.
- the adaptive filter 20 synthesizes a spurious echo signal y′(k) based on the NLMS algorithm from the receiving signal x(k) before being delivered from the speaker 3 .
- This spurious echo signal y′(k) is an echo signal estimated by the adaptive filter 20 and is expressed by Equation (8).
- y ′( k ) h ′( k ) ⁇ x ( k ) Equation (8)
- the parameter h′(k) in Equation (8) is a conversion coefficient from the receiving signal x(k) to the spurious echo signal y′(k).
- the conversion coefficient h′(k) indicates a transmission characteristic of the acoustic echo path from the speaker 3 to the microphone 2 , which is estimated by the adaptive filter 20 .
- the adaptive filter 20 delivers the obtained spurious echo signal y′(k) to the first subtractor 30 .
- the first subtractor 30 receives the input signal yin(k) that is supplied from the microphone 2 . Then, the first subtractor 30 subtracts the above-mentioned spurious echo signal y′(k) from the received input signal yin(k) so as to generate an echo cancellation signal p(k).
- the echo cancellation signal p(k) generated by the first subtractor 30 is expressed by Equation (9).
- Equation (9) indicates an error of echo estimation performed in the adaptive filter 20 and is referred to as a “residual echo signal” in the following description.
- the residual echo suppressor 41 receives the echo cancellation signal p(k) generated by the first subtractor 30 and the input signal yin(k) supplied from the microphone 2 . Then, the residual echo suppressor 41 removes the residual echo signal “y(k) ⁇ y′(k)” from the echo cancellation signal p(k), so as to generate a residual echo cancellation signal q(k). The removal of the residual echo signal “y(k) ⁇ y′(k)” can be performed by using the method described in Japanese Patent Application Laid-open No. 2008-141734.
- the residual echo cancellation signal q(k) generated by the residual echo suppressor 41 is expressed by Equation (10).
- the noise suppressor 42 receives the residual echo cancellation signal q(k) generated by the residual echo suppressor 41 . Then, the noise suppressor 42 removes a noise signal that is equal to the ambient noise signal n(k) from the residual echo cancellation signal q(k).
- the noise suppressor 42 of this embodiment it is possible to use the one described in the paper: “Noise Suppression with High Speech Quality Based on Weighted Noise Estimation and MMSE STSA”, KATO Masanori, SUGIYAMA Akihiko, SERIZAWA Masahiro, Institute of Electronics, Information and Communication Engineers, Papers VOL. J87-A, No. 7, pp. 851-860, July 2004.
- the noise suppressor 42 removes a noise component based on the weighted noise estimation and the MMSE STSA method. More specifically, the noise suppressor 42 uses a degraded voice weighted in accordance with an estimated value of a voice-to-noise ratio so as to update a noise estimated value continuously. The noise estimated value is stored in a predetermined storage unit. Then, the noise suppressor 42 subtracts a noise estimated value n′(k ⁇ 1) that is equal to the ambient noise signal n(k) from a residual echo cancellation signal q(k ⁇ 1) of the previous sampling period so as to generate a spurious voice signal r(k ⁇ 1) expressed by Equation (11).
- the spurious echo signal y′(k) is removed in Step S 2
- the residual echo signal “y(k) ⁇ y′(k)” is removed in Step S 3
- the noise component is removed in Step S 4 . Therefore, the signal r(k ⁇ 1) generated by the noise suppressor 42 is the spurious voice signal corresponding to the voice signal v(k) of the near end talker.
- the noise suppressor 42 removes the noise component from the residual echo cancellation signal q(k) so as to extract the spurious voice signal r(k ⁇ 1).
- the noise suppressor 42 delivers the obtained spurious voice signal r(k ⁇ 1) as a transmitting signal e(k ⁇ 1).
- the transmitting signal e(k ⁇ 1) becomes the spurious voice signal r(k ⁇ 1) that is almost the same as the voice signal v(k ⁇ 1), and hence speech quality can be improved. Further, the noise suppressor 42 delivers the obtained spurious voice signal r(k ⁇ 1) to the second subtractor 43 .
- the second subtractor 43 receives the echo cancellation signal p(k) generated by the first subtractor 30 . In addition, the second subtractor 43 receives the spurious voice signal r(k ⁇ 1) generated by the noise suppressor 42 . Then, the second subtractor 43 subtracts the spurious voice signal r(k ⁇ 1) from the echo cancellation signal p(k) so as to generate a signal s(k ⁇ 1) expressed by Equation (12).
- the ambient noise signal n(k) has a level that can be neglected.
- the spurious voice signal r(k ⁇ 1) has a level corresponding to the voice signal v(k) of the near end talker. Therefore, it can be said that the signal s(k ⁇ 1) generated by the second subtractor 43 indicates a level of the residual echo “y(k) ⁇ y′(k)” as a result of the echo cancellation process. In other words, the signal s(k ⁇ 1) indicates the error of echo estimation in the adaptive filter 20 . In this sense, the signal s(k ⁇ 1) generated by the second subtractor 43 is referred to as an “error signal” in the following description.
- the residual echo suppressor 41 , the noise suppressor 42 and the second subtractor 43 described above constitute the error signal generating circuit 40 for generating the error signal s(k ⁇ 1).
- the error signal generating circuit 40 removes the spurious voice signal r(k ⁇ 1) corresponding to the voice signal v(k) of the talker from the echo cancellation signal p(k) so as to generate the error signal s(k ⁇ 1). Then, the error signal s(k ⁇ 1) generated by the error signal generating circuit 40 is delivered to the adaptive filter 20 . In other words, according to this embodiment, not the transmitting signal but the error signal s(k ⁇ 1) is fed back to the adaptive filter 20 .
- the adaptive filter 20 receives the error signal s(k ⁇ 1) and updates its characteristic so that an amplitude of the error signal s(k ⁇ 1) becomes smaller. In other words, the adaptive filter 20 updates the conversion coefficient h′(k) so that the error signal s(k ⁇ 1) becomes as small as possible.
- This process corresponds to the process of estimating the transmission characteristic h(k) of the acoustic echo path from the speaker 3 to the microphone 2 so that the echo signal y(k) received by the microphone 2 is cancelled.
- the error signal s(k ⁇ 1) indicates an error in the estimation process, and it can be said that the adaptive filter 20 performs the feedback control so that the estimated error s(k ⁇ 1) becomes zero.
- the spurious echo signal y′(k) becomes equal to the actual echo signal y(k) so that the echo can be completely cancelled.
- Steps S 1 to S 6 described above are repeated until the process for the data is finished.
- the adaptive filter 20 performs the feedback control based on the error signal s(k ⁇ 1).
- the error signal s(k ⁇ 1) does not contain a component corresponding to the voice signal v(k). It is because that the error signal generating circuit 40 removes the spurious voice signal r(k ⁇ 1) corresponding to the voice signal v(k) from the echo cancellation signal p(k) so as to generate the error signal s(k ⁇ 1).
- the component corresponding to the voice signal v(k) is eliminated from the error signal s(k ⁇ 1), and hence stability with respect to the disturbance is enhanced in the adaptive filter 20 that performs the feedback control based on the error signal s(k ⁇ 1).
- the performance of the echo canceller 10 is not lowered, whereby a good echo cancellation performance can be realized.
- the echo canceller illustrated in FIG. 4 it is not necessary to determine the step size based on three parameters including the estimated power of the receiving signal x(k), the estimated level of the ambient noise signal n(k), and the estimated level of the voice signal v(k). It is possible to realize a good echo cancellation performance with a simple structure.
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Telephone Function (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
- Circuit For Audible Band Transducer (AREA)
Abstract
Description
y(k)=h(k)×x(k) Equation (1)
yin(k)=v(k)+n(k)+y(k) Equation (2)
y′(k)=h′(k)×x(k) Equation (3)
e(k)=y(k)−y′(k) Equation (5)
y(k)=h(k)×x(k) Equation (6)
yin(k)=v(k)+n(k)+y(k) Equation (7)
y′(k)=h′(k)×x(k) Equation (8)
Claims (6)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/619,836 US8867735B2 (en) | 2008-09-24 | 2012-09-14 | Echo cancelling device, communication device, and echo cancelling method having the error signal generating circuit |
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2008-243702 | 2008-09-24 | ||
JP2008243702A JP2010081004A (en) | 2008-09-24 | 2008-09-24 | Echo canceler, communication apparatus and echo canceling method |
JP243702/2008 | 2008-09-24 | ||
US12/461,329 US8325910B2 (en) | 2008-09-24 | 2009-08-07 | Echo cancelling device, communication device, and echo cancelling method having the error signal generating circuit |
US13/619,836 US8867735B2 (en) | 2008-09-24 | 2012-09-14 | Echo cancelling device, communication device, and echo cancelling method having the error signal generating circuit |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/461,329 Continuation US8325910B2 (en) | 2008-09-24 | 2009-08-07 | Echo cancelling device, communication device, and echo cancelling method having the error signal generating circuit |
Publications (2)
Publication Number | Publication Date |
---|---|
US20130012275A1 US20130012275A1 (en) | 2013-01-10 |
US8867735B2 true US8867735B2 (en) | 2014-10-21 |
Family
ID=42037694
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/461,329 Expired - Fee Related US8325910B2 (en) | 2008-09-24 | 2009-08-07 | Echo cancelling device, communication device, and echo cancelling method having the error signal generating circuit |
US13/619,836 Expired - Fee Related US8867735B2 (en) | 2008-09-24 | 2012-09-14 | Echo cancelling device, communication device, and echo cancelling method having the error signal generating circuit |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/461,329 Expired - Fee Related US8325910B2 (en) | 2008-09-24 | 2009-08-07 | Echo cancelling device, communication device, and echo cancelling method having the error signal generating circuit |
Country Status (2)
Country | Link |
---|---|
US (2) | US8325910B2 (en) |
JP (1) | JP2010081004A (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9595997B1 (en) * | 2013-01-02 | 2017-03-14 | Amazon Technologies, Inc. | Adaption-based reduction of echo and noise |
US9697847B2 (en) | 2013-03-14 | 2017-07-04 | Semiconductor Components Industries, Llc | Acoustic signal processing system capable of detecting double-talk and method |
CN104050971A (en) * | 2013-03-15 | 2014-09-17 | 杜比实验室特许公司 | Acoustic echo mitigating apparatus and method, audio processing apparatus, and voice communication terminal |
US9712866B2 (en) | 2015-04-16 | 2017-07-18 | Comigo Ltd. | Cancelling TV audio disturbance by set-top boxes in conferences |
US9959888B2 (en) * | 2016-08-11 | 2018-05-01 | Qualcomm Incorporated | System and method for detection of the Lombard effect |
WO2019181758A1 (en) | 2018-03-19 | 2019-09-26 | パナソニックIpマネジメント株式会社 | Conversation support device |
US11423921B2 (en) | 2018-06-11 | 2022-08-23 | Sony Corporation | Signal processing device, signal processing method, and program |
CN115133941B (en) * | 2022-05-27 | 2023-09-19 | 南京金阵微电子技术有限公司 | Signal receiving terminal, serializer and communication system |
CN115001518B (en) * | 2022-05-27 | 2023-12-05 | 南京金阵微电子技术有限公司 | Signal receiving circuit, deserializer and communication system |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002076999A (en) | 2000-08-25 | 2002-03-15 | Nec Eng Ltd | Method and device for identifying system |
JP2003249996A (en) | 2002-02-25 | 2003-09-05 | Kobe Steel Ltd | Sound signal input/output device |
US20040125944A1 (en) | 2002-11-29 | 2004-07-01 | Mirjana Popovic | Method of capturing constant echo path information in a full duplex speakerphone using default coefficients |
JP2006033802A (en) | 2004-06-17 | 2006-02-02 | Matsushita Electric Ind Co Ltd | Echo-canceling apparatus, telephone set using the same, and echo-canceling method |
JP2007053511A (en) | 2005-08-17 | 2007-03-01 | Sony Corp | Speech processing device and microphone apparatus |
US20080112568A1 (en) | 2006-11-10 | 2008-05-15 | Yohei Sakuraba | Echo Canceller and Communication Audio Processing Apparatus |
US20080205633A1 (en) * | 2007-02-27 | 2008-08-28 | Freescale Semiconductor, Inc. | Estimating delay of an echo path in a communication system |
US20080240455A1 (en) * | 2007-03-30 | 2008-10-02 | Honda Motor Co., Ltd. | Active noise control apparatus |
US7856097B2 (en) | 2004-06-17 | 2010-12-21 | Panasonic Corporation | Echo canceling apparatus, telephone set using the same, and echo canceling method |
-
2008
- 2008-09-24 JP JP2008243702A patent/JP2010081004A/en active Pending
-
2009
- 2009-08-07 US US12/461,329 patent/US8325910B2/en not_active Expired - Fee Related
-
2012
- 2012-09-14 US US13/619,836 patent/US8867735B2/en not_active Expired - Fee Related
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002076999A (en) | 2000-08-25 | 2002-03-15 | Nec Eng Ltd | Method and device for identifying system |
JP2003249996A (en) | 2002-02-25 | 2003-09-05 | Kobe Steel Ltd | Sound signal input/output device |
US20040125944A1 (en) | 2002-11-29 | 2004-07-01 | Mirjana Popovic | Method of capturing constant echo path information in a full duplex speakerphone using default coefficients |
JP2006033802A (en) | 2004-06-17 | 2006-02-02 | Matsushita Electric Ind Co Ltd | Echo-canceling apparatus, telephone set using the same, and echo-canceling method |
US7856097B2 (en) | 2004-06-17 | 2010-12-21 | Panasonic Corporation | Echo canceling apparatus, telephone set using the same, and echo canceling method |
JP2007053511A (en) | 2005-08-17 | 2007-03-01 | Sony Corp | Speech processing device and microphone apparatus |
US20080112568A1 (en) | 2006-11-10 | 2008-05-15 | Yohei Sakuraba | Echo Canceller and Communication Audio Processing Apparatus |
JP2008141734A (en) | 2006-11-10 | 2008-06-19 | Sony Corp | Echo canceller and communication audio processing apparatus |
US20080205633A1 (en) * | 2007-02-27 | 2008-08-28 | Freescale Semiconductor, Inc. | Estimating delay of an echo path in a communication system |
US20080240455A1 (en) * | 2007-03-30 | 2008-10-02 | Honda Motor Co., Ltd. | Active noise control apparatus |
Non-Patent Citations (2)
Title |
---|
Japanese Office Action dated Sep. 10, 2012 with an English translation thereof. |
U.S. Office Action in U.S. Appl. No. 12/461,329 dated Mar. 20, 2012. |
Also Published As
Publication number | Publication date |
---|---|
JP2010081004A (en) | 2010-04-08 |
US8325910B2 (en) | 2012-12-04 |
US20100074434A1 (en) | 2010-03-25 |
US20130012275A1 (en) | 2013-01-10 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8867735B2 (en) | Echo cancelling device, communication device, and echo cancelling method having the error signal generating circuit | |
EP2171714B1 (en) | A device for and a method of processing audio signals | |
US8311234B2 (en) | Echo canceller and communication audio processing apparatus | |
EP0914721B1 (en) | Echo canceler for non-linear circuits | |
JP5061853B2 (en) | Echo canceller and echo cancel program | |
EP1022866A1 (en) | Echo elimination method, echo canceler and voice switch | |
US9191519B2 (en) | Echo suppressor using past echo path characteristics for updating | |
JP3267556B2 (en) | Echo canceller and transmitter | |
US20050243995A1 (en) | Method and apparatus for canceling acoustic echo in a double-talk period | |
JP4059618B2 (en) | Communication terminal | |
JP2005323084A (en) | Method, device, and program for acoustic echo-canceling | |
US6560332B1 (en) | Methods and apparatus for improving echo suppression in bi-directional communications systems | |
US9858944B1 (en) | Apparatus and method for linear and nonlinear acoustic echo control using additional microphones collocated with a loudspeaker | |
JP2005533427A (en) | Echo canceller with model mismatch compensation | |
JP3082898B2 (en) | Echo canceller | |
US6850783B1 (en) | Methods and apparatus for mitigating the effects of microphone overload in echo cancelation systems | |
JP2007189536A (en) | Acoustic echo canceler, acoustic error canceling method and speech communication equipment | |
JP2861888B2 (en) | Echo / noise canceller and echo / noise elimination method | |
JP3268572B2 (en) | Apparatus and method for canceling echo | |
Raghavendran | Implementation of an acoustic echo canceller using matlab | |
JP2005530443A (en) | Unsteady echo canceller | |
JPH1023172A (en) | Echo eliminating device | |
JPH08288894A (en) | Echo suppression device | |
JP3442535B2 (en) | Echo canceller | |
JPH0514476A (en) | Loudspeaker telephone set |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
AS | Assignment |
Owner name: RENESAS ELECTRONICS CORPORATION, JAPAN Free format text: CHANGE OF ADDRESS;ASSIGNOR:RENESAS ELECTRONICS CORPORATION;REEL/FRAME:044928/0001 Effective date: 20150806 |
|
MAFP | Maintenance fee payment |
Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1551) Year of fee payment: 4 |
|
FEPP | Fee payment procedure |
Free format text: MAINTENANCE FEE REMINDER MAILED (ORIGINAL EVENT CODE: REM.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
LAPS | Lapse for failure to pay maintenance fees |
Free format text: PATENT EXPIRED FOR FAILURE TO PAY MAINTENANCE FEES (ORIGINAL EVENT CODE: EXP.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20221021 |